Ordinary gate valves generally refer to hard-sealed gate valves. This article analyzes in detail the difference between soft-sealed gate valves and ordinary gate valves. If you are satisfied with the answer, please give VTON a thumbs up.
Simply put, elastic soft-sealed gate valves are seals between metals and non-metals, such as nylon\tetrafluoroethylene, and hard-sealed gate valves are seals between metals and metals;
Soft-sealed gate valves and hard-sealed gate valves refer to the sealing materials of the valve seat. Hard seals are precisely machined with valve seat materials to ensure the matching accuracy with the valve core (ball), generally stainless steel and copper. Soft seals refer to the sealing materials embedded in the valve seat as non-metallic materials. Because soft seal materials have a certain elasticity, the processing accuracy requirements are relatively lower than hard seals. We refer to the characteristics of VTON to describe the difference between imported soft-sealed gate valves and imported hard-sealed gate valves.
1. Sealing materials
1. The sealing materials of the two are different. Soft-sealed gate valves are generally made of rubber or polytetrafluoroethylene. Hard-sealed gate valves are made of metals such as stainless steel.
2. Soft seal: The seal pair is made of metal material on one side and elastic non-metal material on the other side, which is called “soft seal”. This kind of seal has good sealing performance, but is not resistant to high temperature, easy to wear, and has poor mechanical properties. For example: steel rubber; steel tetrafluoroethylene, etc. For example, the imported elastic seat seal gate valve of VTON is generally used at a temperature less than 100℃, and is mostly used for room temperature water.
3. Hard seal: The seal pair is made of metal material or other harder materials on both sides, which is called “hard seal”. This kind of seal has poor sealing performance, but is resistant to high temperature, wear and has good mechanical properties. For example: steel steel; steel copper; steel graphite; steel alloy steel; (the steel here may also be cast iron, cast steel, alloy steel may also be surfacing, sprayed alloy). For example, the imported stainless steel gate valve of VTON can be used for steam, gas, oil and water, etc.
2. Construction technology
The mission environment of the machinery industry is complex, many of which are ultra-low temperature and low pressure, with large resistance and strong corrosiveness of the medium. Now the technology has improved, so that hard-sealed gate valves have been widely promoted.
The hardness relationship between metals should be taken into account. In fact, the hard-sealed gate valve is the same as the soft-sealed one because it is a seal between metals. The valve body is required to be hardened, and the valve plate and the valve seat must be continuously ground to achieve sealing. The production cycle of hard-sealed gate valves is long.
3. Use conditions
Sealing effect Soft seals can achieve zero leakage, while hard seals can be high or low according to requirements;
Soft seals need to be fireproof, and leakage will occur at high temperatures, while hard seals will not leak. Emergency shut-off valve hard seals can be used under high pressure, while soft seals cannot be used. At this time, VTON’s hard-sealed gate valve is needed.
Soft seals should not be used on certain corrosive media, and hard seals can be used;
4. Operating conditions
Hard seals can be high or low according to requirements; soft seals must be fireproof, and soft seals can achieve high individual seals. Because at ultra-low temperatures, soft seals will leak, while hard seals do not have this problem; hard seals can generally withstand very high pressures, while soft seals cannot. For example, the imported forged steel gate valves of VTON use hard seals, and the pressure can reach 32Mpa or 2500LB; soft seals cannot be used in some places due to the flow of the medium, such as some corrosive media); finally, hard seal valves are generally more expensive than soft seals. As for the construction, the difference between the two is not big, the main difference is the valve seat, the soft seal is non-metallic, and the hard seal is metal
V. Equipment selection
The selection of soft and hard seal gate valves is mainly based on the process medium, temperature and pressure. Generally, if the medium contains solid particles or has wear or the temperature is higher than 200 degrees, it is best to use hard seals. For example, high-temperature steam is generally around 180-350℃, so a hard seal gate valve must be selected.
6. Difference in price and cost
For the same caliber, pressure and material, imported hard-sealed gate valves are much more expensive than imported soft-sealed gate valves; for example, VTON’s DN100 imported cast steel gate valve is 40% more expensive than DN100 imported cast steel soft-sealed gate valve; if both hard-sealed gate valves and soft-sealed gate valves can be used under the working conditions, when considering the cost, try to choose imported soft-sealed gate valves.
7. Difference in service life
Soft seal means that one side of the seal pair is made of a material with relatively low hardness. Generally speaking, the soft seal seat is made of non-metallic materials with certain strength, hardness and temperature resistance. It has good sealing performance and can achieve zero leakage, but its life and adaptability to temperature are relatively poor. Hard seals are made of metal and have relatively poor sealing performance, although some manufacturers claim that they can achieve zero leakage.
The advantage of soft seals is good sealing performance, and the disadvantage is easy aging, wear and tear, and short service life. Hard seals have a long service life, but their sealing performance is relatively poor compared to soft seals. These two types of seals can complement each other. In terms of sealing, soft seals are relatively better, but now the sealing of hard seals can also meet the corresponding requirements.
Soft seals cannot meet the process requirements for some corrosive materials, but hard seals can solve this problem!
These two types of seals can complement each other. In terms of sealing, soft seals are relatively better, but now the sealing of hard seals can also meet the corresponding requirements!
The advantage of soft seals is good sealing performance, and the disadvantage is easy aging, wear and tear, and short service life.
Hard seals have a long service life, but the sealing is relatively worse than soft seals.
Post time: Dec-14-2024
